Flush-type toggle latch



July 31, 1962 A. F. GANDER FLUSH-TYPE TOGGLE LATCH 2 Sheetsl-Sheet 1Filed Aug. 26, 1959 INVENToR. Hander July 31, 1962 A. F. GANDER3,047,321

FLUSH-TYPE TOGGLE LATCH Filed Aug. 26, 1959 2 Sheets-Sheet 2 INVENToR.Arnold l? @ander www United States Patent O 3,047,321 FLUSH-TYPE TOGGLELATCH Arnold F. Gander, Berkeley, Calif.

Filed Aug. 26, 1959, Ser. No. 836,255 3 Claims. (Cl. 292-223) Thisinvention relates to toggle type latch mechanisms which are adapted tomounting with an actuating element in substantially flush relationshipto a door surface in one of the operating positions of the latch, andmore particularly to such latch mechanisms incorporating structuralfeatures affording improved safety and more general adaptability in use.

The flush-type toggle latch which is disclosed herein is, in certainrespects, somewhat similar to the latch shown in my United States PatentNo. 2,621,952, issued December 16, 1952, for Flush-Type Toggle Latch.

One of the objects of this invention is to provide a toggle type latchincorporating spring means for biasing operating parts of the latch topositions to which they were last operated, and wherein said springmeans has a plurality of portions which normally aid one another inproviding the biasing forces, and various ones of which portions couldbreak during use vvithou-t defeating the operability of the latch,thereby affording a safety factor during use.

As another object, my invention has within its purview the provision ofa toggle type latch having a single actuating element which is rockedlongitudinally in a unitary opening in a door panel or the like as aresult of manual forces applied at one or the other end thereof foreffecting actuation `of the latch.

It is another object of this invention :to provide a toggle type latchmechanism having an adjustable gripping element on the keeper whichadapts the latch to use with door jambs of various thicknesses.

Other objects and advantages lof fthe invention will be apparent fromthe lfollowing description and the accompanying drawings in whichsimilar characters of reference indicate similar parts throughout theseveral views.

FIG. l is a front elevational view of a flush-type toggle latch adaptedto use on airplane doors and the like which latch embodies a preferredform of my invention, and in which view a door upon which the latch ismounted is depicted fragmentarily in dot and dash lines;

FIG. 2 is a rear elevational view of the latch shown in FIG. 1, with thedoor and an associated jamb illustrated fragmentarily;

FIG. 3 is a side sectional view wherein the section is takensubstantially as indicated by a line 3 3 and accompanying arrows in FIG.2, the latch mechanism being shovm in its holding position;

FIG. 4 is a side elevational view of the ldisclosed flushtype togglelatch, wherein the latch mechanism is shown in its retracted positionand the door and jamb are illustrated fragmentarily in dot and dashlines;

FIGS. 5 and 6 are respectively side elevational and top plan views of aresilient spring element of a preferred form which is adapted to use inthe mechanism of the flush-type toggle latch shown in FIGS. 1 to 4inclusive, the parts of the spring being illustrated in their normal orunwound positions;

FIG. 7 is a view similar to FIG. 3 showing a flushtype toggle latchmechanism in which some of the parts are of modified structure;

FIG. 8 is a side elevational view similar to FIG. 4, but depicting themodified structure of FIG. 7 in its released position;

FIGS. 9 and l0 are respectively side elevational and top plan views Vofa type of spring different than that shown in FIGS. 5 and 6 which isused in the latch mechanism of 3,047,32l Fatented July 3l, 1962 2 FIGS.7 and 8, the parts of the spring being illustrated in their normal orunwound positions;

FIG. 11 is a side elevational view of the spring of FIGS. 9 and 10 withthe parts thereof in the positions assumed when the latch is in theholding position, as shown in FIG. 7, and wherein other positions of thespring parts corresponding 'to different positions of the latchmechanism are shown in dot and dash lines; and

FIGS. 12 and 13 are fragmentary side elevational views similar to FIG.l1 but providing exemplary illustrations of positions of parts of thespring which would exist if different portions of the spring wouldbreak.

Although the illustrated flush-type toggle latch is not limited to useon airplane doors, it is shown in forms which are adapted to such use.When mounted as shown, the unitary actuator for the latch is exposed onan exterior surface `of a door, and when disposed for holding the doorin a closed position, the actuator is substantially flush with .the doorsurface and is provided with a gasket which serves as an air andweatherproof seal. In use, the illustrated latch is biased to theposition to which it is last operated by manual movement `of the latchactuator and incorporates a biasing spring which affords a safety factorby having parts which function to maintain the latch in its holdingposition, even if some portion of the spring breaks as a result offatigue or for any other reasons. The illustrated latch structurefurther incorporates an adjustable element which is adapted toaccommodate jambs of various thicknesses and to insure that the door isheld tightly closed.

Having reference ,to the drawings, and particularly FIGS. l to 6thereof, wherein an exemplary embodiment of the invention is shown forillustrative purposes, my flush-type toggle latch 15 has 4a base plate16 presenting a substantially flat mounting surface 17 and having holes13 therein at spaced positions for the accommodation of fastening means,such as rivets 19, by which the base plate is secured to the surface of-a structure, such as a door, upon which the toggle latch is to hemounted. At the midportion of one end of the base plate 16, -a recess 20is cut therein to provide metal on opposite sides of the recess for theintegral formation of lugs 22 which project in substantially rightangular relationship from the rear surface of the base plate. The lugs22 `are in spaced and opposed relationship to one another.

At the mid-portion of the end of the base plate opposite the recess 20,a slot 23 extends through the `base plate and has integral lugs 24formed on opposite sides thereof adjacent the end of the base plate andin spaced and opposed relationship to one another. The lugs 24, like thelugs 2-2, project in substantially right angular relationship from therear surface of the base plate and are formed With reference 'to alongitudinal center line which coincides with that of the lugs 22, sothat the parts of lugs at the opposite ends of the base plate are inaligned relationship.

A latch actuator Z5 includes a channel member 26 having side portions 27which `fi-t movably between the lugs 24 on the base plate and a webportion 28 to which a unit-ary actuating plate 29 is secured byfastening means, such as'rivets 30. A cross pin 32 extends throughaligned openings in the lugs 24 and in the longidutinal mid-portions ofthe side flanges 27 of the channel member 26 to support the latchactuator for swinging movements around the adjacent end of `the baseplate 16. In the disclosed structure, the mounting of the latch actuator25 relative to the base plate 16 provides space lbetween the surfaces ofthe base plate -and actuating plate for a gasket 33 of a resilientmaterial, such as rubber, which gasket covers the back surface of theactuating plate, `as shown in FIG. 3, and serves as a weatherproof sealbetween the actuating plate and the surface of the base plate `adjacentthe slot 23. An additional resilient gasket 34 is secured to the backsurface of the gasket 33 adjacent the channel member 26 at the end ofthe actuating plate which extends beyond the base plate I6. This gasket34 extends beyond the end and sides of the actuating plate 23 to providean exposed marginal portion 35 which is adapted to engage the surface ofa structure, such as a door 36, as shown in FIGS. 2, 3 and 4. In use,the actuating plate 29 tits into a substantially conforming opening 37in the door 36 when the surface 17 of the base plate is mounted againstthe rear or inner surface of the door.

Particularly when used on airplane doors, the gasket 33 and actuatingplate 29 have thicknesses which conform substantially to the thicknessof the door 36, so that when mounted as described, the exposed outersurface of the actuating plate is substantially ilush with the surfaceof the door. With this arrangement, also, the gaskets 33 and 34 providea weather seal around the actuating plate. In the form disclosed, theactuating plate is of substantially uniform width at its longitudinalmidportion `and is rounded at its opposite ends. Being hinged forswinging movement at its longitudinal mid-portion by the cross pin 32around the end of the base plate 16, the latch actuator overlaps asubstantial portion of the base plate upon which it is mounted. Itrequires only a single opening in the door Vaffording adequate room foroperation without danger of having an operator get a finger caught in asmall door opening; the direction of operation or movement of the latchactuator being dependent upon the end of the actuating plate to whichmanual pressure is applied.

A latch bolt 38 has side flange portions 39 adjoined by web portion 4Qand which fit movably between the lugs 2.2 at the end of the base plateopposite the latch actuator 25. A cross pin 42 extends through alignedopenings in the lugs 22 and side flange portions 39 to support the latchbolt 38 for swinging movement between positions including one in whichthe latch bolt extends beyond the base plate, as shown in FIGS. l, 2 and3, `and one in which it is withdrawn behind the base plate, as shown inFIG. 4. The side flange portions 39 of the latch fbolt are cut away atthe end remote from the cross pin 42 to provide space for a jambengaging element 43 which includes a head portion 44 and a threaded stemportion 45. The stern portion 45 is threaded into the web portion 40 ofthe latch bolt at a position spaced from the cross pin 42, so that itsposition is adjustable relative to the web portion 40. A lock nut 46 isprovided for securing the jamb engaging element 43 in a fixed positionrelative to the web portion 40. In the operation of the latch the endsurface of the head portion 44 of the jamb engaging element engages thesurface of a jamb strip 47, as shown in FIGS. 2 and 3, when the latchbolt is in its holding position. When retracted, the end of the headportion 44 of the jamb engaging element is withdrawn to a positionbehind the base plate 16, as shown in FIG. 4, so that the latch boltwill pass through the door opening.

The latch actuator 25 is movably and operatively connected to the latchbolt 38 by a channel-type link 4S having side flange portions 49 and aweb portion 50. The side flange portions 49 of the link 4S movably titbetween the side flange portions Si) of the channel member 26 of thelatch actuator and between the side flange portions 39 of the latch bolt38. At one end, a cross pin 52 extends through aligned openings in theside flange portions 27 on the latch actuator and the side flangeportions 49 of the link to provide a movable connection therebetween. Atthe other end of the link 43, a cross pin 53 extends through alignedopenings in the side flange portions 39 of the latch bolt and the sideflange portions 49 of the link to provide a movable connection betweenthose parts of the latch mechanism.

The axes of the cross pins 32, 42, 52 and 53 which afford movablesupports for the latch actuator and latch bolt and movable connectionsbetween the link and the latch actuator and latch bolt are substantiallyparallel to one another. As shown in FIGS. 3 and 4, it may be observedthat the tixed axis 32, about which the latch actuator moves, and themovable axes of the cross pins 52 and 53 which connect the latchactuator, link, and latch bolt are disposed at the vertices of atriangle having dilerent shapes in the holding and retracted positionsof the latch bolt. It may also be observed that the axes of those crosspins are close to being disposed in a common plane when the latchmechanism is in the holding position depicted in FIG. 3, and passthrough a position of alignment in that common plane when the latch ismoved from the holding position of FIG. 3 to the retracted position ofFIG. 4. Also, the fixed axis of the cross pin 42 about which the latchbolt swings and the axes of the cross pins 52 and 53 which connect thelatch actuator, link, and latch bolt are located at the vertices ofanother triangle which varies in shape as the latch bolt swings betweenthe latch holding and retracted positions.

In the latch holding position shown in FIG. 3, the angle between a planepassing through the axes of the cross pins 42 and 53 and a plane passingthrough the axes of the cross pins 52 and 53 is an acute angle. Withthis arrangement of parts and with this disposition of the cross pins32, 42, 52 and 53, it may be understood that pressure exerted againstthe latch bolt which would tend to effect movement thereof to itsretracted position for opening the door will urge the latch actuatoragainst the base plate and will thus resist forces tending to open thedoor when the latch bolt is in the holding position. However, swingingmovement of the latch actuator toward a position in which the latch boltis retracted will move the axis of the cross pin 52 through a planeconnecting the axes of the cross pins 32 and 53, and when that plane ispassed by the axis of the cross pin 52, any force applied to the latchbolt tending to move it to the retracted position will effectcontinuance of the movement of the latch actuator and latch bolt towardthe retracted position shown in FIG. 4. It may thus be understood thatwhen the latch is in its holding position, any force, such as that of aspring, which maintains the cross pins 32, 52 and 53 in their normalpositions with the latch bolt in the holding position shown in FIG. 3will practically insure the retention of the door in its closed positionunless the latch mechanism is operated by the application of force tothe latch actuator.

For insuring the retention of the axes of the cross pins in properpositions for securing the door in its closed position when the latchbolt is in its holding position and for effecting snap action of thelatch mechanism in both directions when operated by the latch actuator,as well as for providing a safety lfactor for insuring such operation ofthe latch mechanism, I have provided a resilient spring 54 which isillustrated in FIGS. 5 and 6 and shown in its operative arrangement inthe latch mechanism in FIGS. l to 4 inclusive. The spring 54 has coilportions S5 and 56 in axially spaced and substantially coaxialrelationship to one another. At adjacent ends of the coil portions 55and 56, integral arm portions 57 and 58 respectively extend therefrom inspaced and substantially parallel relationship to one another and areintegrally adjoined at the ends remote from the coil portions by aconnecting portion 59. At the other ends of each of the coil portions 55and 56, integral arm portions 60 and 62 extend therefrom insubstantially parallel and spaced relationship to one another. In itsapplication to the described latch mechanism, the coil portions 55 and56 encompass the cross pin 53 which connects the link 43 to the latchbolt 38. The arm portions 60 and 62 have loops 63 and 64 on the endsthereof which engage the cross pin 42 by which the latch bolt is movablyconnected to the base plate. Also, arms 57 and 58 have hook portions,such as 65 on the ends thereof which engage the cross pin 52 `by whichthe latch actuator is connected to the link.

In the normal or unwound position of the spring 54,

the arm portions assume angles with reference to the axes of the coilportions which are indicated in FIG. 5 by lines a and b. When the spring54 is in place on the `cross pins 52, 53 and 42, as `shown -in FIG. 3,it is always under stress and in a position to exert a biasing forceagainst the engaged cross pins. As shown in FIG. 5, the angle betweenthe spring arms Awhen the latch is in its holding position is indicatedby the lines a and c, While in the released position, the spring angleis represented by the lines a and d. Being continually under stress, itmay be understood that the latch is always biased to the position towhich it is last operated by the latch actuator, and Ithat the eiiectivedirection of action of the biasing force on the moving parts of thelatch mechanism transfers between the holding and retracted positionswhen the axis of the cross pin 52 crosses the plane defined by the axesof the cross pins 32 and 53.

In the modified structure of my flush-type toggle latch which isillustrated in FIGS. 7-13 inclusive, the latch parts, including the baseplate 16, the lugs 22 and 2li on the base plate, the latch actuator 25,the latch bolt 3S, the ling 48 and the cross pins 32, d2, 52 and 53 areessentially the same as those described, and those parts are eachadapted to function in the manner described. However, in this modifiedstructure, a spring 65, of the type illustrated in FIGS. 9 and 10, isutilized to efect the snap action of the latch mechanism, to provide thebiasing forces for holding the latch mechanism in the position to whichit is last operated and to provide a safety factor for holding the latchin its holding position in the event of a failure of a part of thespring.

As illustrated in FIGS. 9 and 10, the spring 65 has coil portions 66 and67 in spaced relationship to one another and integrally connected by anarm portion 68 which adjoins corresponding and substantially alignedends of the coil portions. At the end of the coil portion 66 oppositethe arm portion 6g, an integral arm portion 69 extends from the coilportion in angular relationship to the arm portion 68. Also, at the endof the coil portion 67 opposite the arm portion 68 an integral armportion 70 extends from that coil portion in angular relationship to thearm portion 68. The parts of the spring are shown in their normal orunsprung positions in FIGS. 9 and 10.

In use on the illustrated latch mechanism, the coil portions 66 and 67of the spring 65 encompass the cross pins S2 annd 53 at the oppositeends of the link 48. The arm portion 70 has an end loop 72 thereon whichengages the cross pin 42 upon which the latch bolt is mounted forswinging movement. The arm portion 69 has a loop 73 on the end thereofremote from the coil portion 66 which engages the coil pin 32 upon whichthe latch actuator is mounted for rocking movement relative to the endof the base plate 16. When thus engaged with the cross pins, theportions of the spring 65 are continually stressed. That is, as shown inFIG. 1l7 the angles between the spring arms in the normal or unsprungpositions of the arms are designated as A and A. When the spring isinstalled in the latch mechanism and the latch parts are in theirreleased positions, the angles between the arms are designated as B andB. When the latch is in its holding position, the angles C and Crepresent the displacements of the arm portions of the spring. Also, itmay be observed that as the latch mechanism moves through its centerposition, at which the axis of the cross pin 52 crosses the planedefined by the axes of the cross pins 32 and 53, the angles between thearm portions of the spring are designated as D and D'.

As indicated in FIG. 12, breakage of the spring arm 70 would leave thearm portions 68 and 69 in operative condition to exert biasing force forholding the latch mechanism in its holding position. Likewise, as shownin PIG. 13, breakage of the arm portion 69 of the spring would leave thearm portions 68 and 70 in operative condition to exert biasing force forretaining the latch mechanism in either its holding or releasedposition.

Thus, by reference to the drawings and the description of the structureand operation of the disclosed latch mechanism, it may be observed thatI have provided a flush-type toggle latch having a unitary actuator, alatch bolt which is adjustable to accommodate door jambs of variousthicknesses and I have utilized in this latch structure springs whichafford a factor of safety by maintaining the operativeness of the latch,even though a p0rtion of the spring breaks.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In a hush-type toggle latch mechanism, the combination comprising abase member having an open slot at one end which extends to themid-portion thereof, a latch actuator having a portion mounted in saidslot and including an actuating plate with one end of a size forcovering said slot and an opposite end portion extending outwardly fromthe base member, a cross pin providing a fixed axis and supporting thelatch actuator at its midportion for rocking movements relative to saidone end of the base member between a latching position substantiallyparallel to the base member and a releasing position in angular relationto the base member, a latch bolt, a second cross pin providing a xedaxis and supporting the latch bolt for swinging movements relative tothe end of the base opposite said open slot, said latch bolt having aholding position in which it projects beyond the end of the baseopposite said open slot and a retracted position in which it iswithdrawn from the holding position and extends angularly from the basemember, a link having opposite ends movably connected by cross pins tothe latch actuator and latch bolt for effecting movements of the latchbolt between said holding and retracted positions in response to said'rocking movements of the latch actuator between said latching andreleasing positions by pressure applied to opposite end pox'- tions ofsaid actuating plate, unitary spring means including a plurality of coilportions with integral arm portions on opposite ends of each of the coilportions, said arm portions on each of the coil portions having normalunsprung positions in predetermined angular relationship to one another,each coil portion encompassing one of said cross pins and the armportions thereon having engagement with cross pins other than said oneand exerting forces thereon in the same directions in all positions ofthe latch mechanism.

2. In a Hush-type toggle latch mechanism as defined in claim 1, the coilportions of said spring means having substantially parallel axes spacedfrom one another and two of said ends thereof being integrally adjoinedthrough one of said arm portions, and the arm portions ron the otherends of the coil portions normally extend- References Cited in the fileof this patent UNITED STATES PATENTS 1,482,049 Swanson Jan. 29, 19242,092,395 Hill Sept. 7, 1937 2,479,921 Gander Aug. 23, 1949 2,621,952Gander Dec. 16, 1952 2,639,178 Hogan May 19, 1953 2,921,810 Smith Ian.19, 1960

